Intracellular receptors (IRs) form a class of structurally-related genetic regulators scientists have named "ligand dependent transcription factors." R. M. Evans, 240 Science, 889 (1988). Steroid receptors are a recognized subset of the IRs, including the progesterone receptor (PR), androgen receptor (AR), estrogen receptor (ER), glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). Regulation of a gene by such factors requires both the IR itself and a corresponding ligand which has the ability to selectively bind to the IR in a way that affects gene transcription.
Ligands to the IRs can include low molecular weight native molecules, such as the hormones progesterone, estrogen and testosterone, as well as synthetic derivative compounds such as medroxyprogesterone acetate, diethylstilbesterol and 19-nortestosterone. These ligands, when present in the fluid surrounding a cell, pass through the outer cell membrane by passive diffusion and bind to specific IR proteins to create a ligand/receptor complex. This complex then translocates to the cell's nucleus, where it binds to a specific gene or genes present in the cell's DNA. Once bound to DNA, the complex modulates the production of the protein encoded by that gene. In this regard, a compound which binds an IR and mimics the effect of the native ligand is referred to as an "agonist", while a compound that inhibits the effect of the native ligand is called an "antagonist."
Ligands to the steroid receptors are known to play an important role in health of both women and men. For example, the native female ligand, progesterone, as well as synthetic analogues, such as norgestrel (18-homonorethisterone) and norethisterone (17.alpha.-ethinyl-19-nortestosterone), are used in birth control formulations, typically in combination with the female hormone estrogen or synthetic estrogen analogues, as effective modulators of both PR and ER. On the other hand, antagonists to PR are potentially useful in treating chronic disorders, such as certain hormone dependent cancers of the breast, ovaries, and uterus, and in treating non-malignant conditions such as uterine fibroids and endometriosis, a leading cause of infertility in women. Similarly, AR antagonists, such as cyproterone acetate and flutamide have proved useful in the treatment of hyperplasia and cancer of the prostate.
The effectiveness of known modulators of steroid receptors is often tempered by their undesired side-effect profile, particularly during long-term administration. For example, the effectiveness of progesterone and estrogen agonists, such as norgestrel and diethylstilbesterol respectively, as female birth control agents must be weighed against the increased risk of breast cancer and heart disease to women taking such agents. Similarly, the progesterone antagonist, mifepristone (RU486), if administered for chronic indications, such as uterine fibroids, endometriosis and certain hormone-dependent cancers, could lead to homeostatic imbalances in a patient due to its inherent cross-reactivity as a GR antagonist. Accordingly, identification of compounds which have good specificity for one or more steroid receptors, but which have reduced or no cross-reactivity for other steroid or intracellular receptors, would be of significant value in the treatment of male and female hormone responsive diseases.
A group of quinoline analogs having an adjacent polynucleic ring system of the indene or fluorene series or an adjacent polynucleic heterocyclic ring system with substituents having a nonionic character have been described as photoconductive reducing agents, stabilizers, laser dyes and antioxidants. See e.g., U.S. Pat. Nos. 3,798,031; 3,830,647; 3,832,171; 3,928,686; 3,979,394; 4,943,502 and 5,147,844 as well as Soviet Patent No. 555,119; R. L. Atkins and D. E. Bliss, "Substituted Coumarins and Azacoumarins: Synthesis and Fluorescent Properties", 43 J. Org. Chem., 1975 (1978), E. R. Bissell et al., "Synthesis and Chemistry of 7-Amino-4-(trifluoromethyl)coumarin and Its Amino Acid and Peptide Derivatives", 45 J. Org. Chem., 2283 (1980) and G. N. Gromova and K. G. Piotrovskii, "Relative Volatility of Stabilizers for Polymer Materials," 43 Khim. Prom-st., 97 (Moscow, 1967). However, no biological activity of any kind has been ascribed to these compounds.